With surround sound systems in many homes, long wires have created problems for the end consumer. Wires create an unattractive environment and a safety risk. Manufacturers of speaker systems have sought to solve this problem by introducing wireless speaker systems. Initial attempts involved one-way transmission to the speakers of a 900 MHz signal, which can interfere with cordless telephones and other devices in this frequency range. Other solutions include one-way transmission of an audio signal to the speakers via infrared or over power lines in the walls. Most systems send extra control and error correction data on the one-way channel to improve quality of service, since reception of all the data is critical in audio applications. Most wireless speaker systems use a broadcast model for one-way transmission.
FIG. 1 illustrates a conventional one-way wireless speaker system. Digital audio content 101 can come from a CD player or other audio source and is passed to the audio hub 102 where it is split into six components: left; right; center; rear left; rear right; and subwoofer. The wireless transmitter 103 modulates six separate carrier signals with the digital audio information. The six one-way broadcast signals 104 contain player content and reader identification. One-way broadcasts are sent to all channels with each receiver 111 through 116 extracting the broadcast signals. Demodulation is accomplished in blocks 121 through 126 with audio signals as outputs for each speaker channel. Blocks 131 through 136 perform audio signal processing for presentation to the respective speakers.
Frequency hopping is employed at the transmitter allowing the receiver to extract from an individual frequency or alternately every speaker receives the entire signal and parses/extracts its channel. One-way transmission necessitates error correction processing at the receiver using the redundancy introduced into the transmitted signal.